41:9 Say: “What! will you indeed deny Him who created the earth in two periods, and do you ascribe unto Him associates? That is the Rabb of the worlds.”

41:9 The word yawm literally means days, however metonymically it means stages and epochs of million of years. Early interpretations mostly understood yawm literally, in the sense of 24-hour earthly-days. The concept of earth-bound day is not the same with Allāh. When earth was not yet created and its day-length not yet determined, its creation could not have been measured in 24-hour earthly days. Furthermore, the hourly span of a day is different planet to planet: in Jupiter it is 10 earth-hours, in Neptune it is 16 earth-hours, in Venus it is 243 earth-hours. The ‘two periods’ evidently provides an abstract of entire history of the earth’s formation – from the time it was a cosmic matter spun off from the sun to its cooling off to become conducive to sustain life forms.